The present invention relates to an intake device of an engine having plural cylinders arranged in a line, and in particular relates to an intake device of an engine comprising a water-cooling type of intercooler which is installed in an intake manifold.
As the temperature of intake air of an internal combustion engine becomes lower, the mass of the intake air per a unit volume becomes more (the charging efficiency increases). Accordingly, for the engine equipped with a supercharger, an intercooler to cool the intake air compressed by the supercharger may be necessary for increasing the charging efficiency.
Herein, a water-cooling type of intercooler may be more desirable than an air-cooling type of intercooler from viewpoints of the cooling efficiency. Also, it may be desirable to install such an intercooler in an intake-system component for a properly-compact engine room which can provide a roomy vehicle compartment. PCT Patent Application Publication No. WO2009003562A1, for example, discloses an intake device, in which a water-cooling type of intercooler having a laterally-long shape is installed in an intake manifold including a branch pipe portion connecting to respective cylinders and a chamber portion arranged upstream of the branch pipe portion so as to vertically partition a space inside the chamber portion into upper and lower parts.
According to the intake device disclosed in the above-described patent document, there may be no need of arranging another water-cooling type of intercooler in an engine room additionally. Therefore, this device may be more advantageous than an intake device in which no intercooler is installed in the intake manifold in order to provide the properly-compact engine room.
However, the intercooler of the above-described patent document partitions the space inside the chamber portion vertically, in other words, this intercooler is provided such that its intake-air passing faces face to each other in a vertical direction. Accordingly, in order to ensure the area of the intake-air passing faces effectively, it may necessary to make the intercooler expand in an engine longitudinal direction or an engine width direction. Therefore, the intercooler of the above-described patent document is configured to have the laterally-long shape, so that it may have some problem from viewpoints of the compactness in the engine longitudinal direction and the engine width direction.